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Acanthamoeba Keratitis Fact Sheet
Infection of the Eye with Acanthamoeba (A-kanth-a-ME-buh)
- What is Acanthamoeba keratitis?
- What are the symptoms of infection?
- Who is at risk for infection?
- How is Acanthamoeba diagnosed and treated?
- What can I do to decrease my risk of developing Acanthamoeba keratitis?
What is Acanthamoeba keratitis?
Acanthamoeba keratitis is a rare but serious infection of the eye that can result in permanent visual impairment or blindness. The infection is caused when a microscopic, free-living ameba called Acanthamoeba invades the transparent outer covering of the eye called the cornea. These amebas are very common in nature and can be found in all areas of the environment, including water, soil, and air.
What are the symptoms of infection?
Early in the infection, the symptoms of Acanthamoeba keratitis can be very similar to the symptoms of other more common eye infections. The symptoms, which can last several weeks to months, are not the same for everybody and might include:
- Eye pain
- Eye redness
- Blurred vision
- Sensitivity to light
- Sensation of something in the eye
- Excessive tearing
Patients should consult with their eye doctor if they have any of the above symptoms. Acanthamoeba keratitis will eventually cause severe pain and possible vision loss or blindness if untreated.
Who is at risk for infection?
Acanthamoeba keratitis primarily occurs in people who wear contact lenses, but anyone can develop the infection. Individuals with safe contact lens-care practices can develop infection. However, there are several practices among contact lens users that increase the risk of getting Acanthamoeba keratitis including:
- Improper storage and handling of lenses
- Improper disinfection of lenses (such as using tap water or homemade solutions to clean the lenses)
- Swimming, using a hot tub, or showering while wearing lenses
- Coming into contact with contaminated water
- Having a history of trauma to the cornea
How is Acanthamoeba keratitis diagnosed and treated?
Early diagnosis is essential for effective treatment of Acanthamoeba keratitis. The infection is usually diagnosed by an eye specialist based on symptoms, growth of the ameba from a scraping of the eye, and/or seeing the ameba by a process called confocal microscopy. The infection is treated with one or more prescription eye medications. The infection can sometimes be difficult to treat and the best treatment regimen for each patient should be determined by an eye specialist.
What can I do to reduce my risk of developing Acanthamoeba keratitis?
These guidelines should be followed by all contact lens users to help reduce the risk of eye infections, including Acanthamoeba keratitis:
- Visit your eye care provider for regular eye examinations.
- Wear and replace contact lenses according to the schedule prescribed by your eye care provider.
- Remove contact lenses before any activity involving contact with water, including showering, using a hot tub, or swimming. Extended-wear contact lens users should discuss concerns with their eye care provider.
- Wash hands with soap and water and dry before handling contact lenses.
- Clean contact lenses according to the manufacturer's guidelines and instructions from your eye care provider.
- Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored. Never reuse or top off old solution.
- Never use saline solution and rewetting drops to disinfect lenses. Neither solution is an effective or approved disinfectant.
- Store reusable lenses in the proper storage case.
- Storage cases should be rinsed with sterile contact lens solution (never use tap water) and left open to dry after each use.
- Replace storage cases at least once every three months.
This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider.